Bypasses of the gastroenterological (GI), cardiovascular, or urological systems are typically formed by cutting holes in tissues at two locations and joining the holes with sutures or staples. A bypass is typically placed to route fluids (e.g., blood, nutrients) between healthier portions of the system, while bypassing diseases or malfunctioning tissues. The procedure is typically invasive, and subjects a patient to risks such as bleeding, infection, pain, and adverse reaction to anesthesia. Additionally, a bypass created with sutures or staples can be complicated by post-operative leaks and adhesions. Leaks may result in infection or sepsis, while adhesions can result in complications such as bowel strangulation and obstruction. While traditional bypass procedures can be completed with an endoscope, laparoscope, or robot, it can be time consuming to join the holes cut into the tissues. Furthermore, such procedures require specialized expertise and equipment that is not available at many surgical facilities.
As an alternative to sutures or staples, surgeons can use mechanical couplings or magnets to create a compressive anastomosis between tissues. For example, compressive couplings or paired magnets can be delivered to tissues to be joined. Because of the strong compression, the tissue trapped between the couplings or magnets is cut off from its blood supply. Under these conditions, the tissue becomes necrotic and degenerates, and at the same time, new tissue grows around points of compression, e.g., on the edges of the coupling. With time, the coupling can be removed, leaving a healed anastomosis between the tissues.
Nonetheless, the difficulty of placing the magnets or couplings limits the locations that compressive anastomosis can be used. In most cases, the magnets or couplings have to be delivered as two separate assemblies, requiring either an open surgical field or a bulky delivery device. For example, existing magnetic compression devices are limited to structures small enough to be deployed with a delivery conduit e.g., an endoscopic instrument channel or laparoscopic port. When these smaller structures are used, the formed anastomosis is small and suffers from short-term patency.
An additional difficulty arises in that a surgeon typically cannot control the amount of magnetic attraction between deployable magnetic structures used to create an anastomosis. In some instances, it is beneficial for the magnetic devices to couple strongly at distances over 1 cm, however, in other instances, it is beneficial if the devices couple weakly at over 1 cm, and then lock together at a smaller distances. When the magnetic force is stronger than needed for a procedure, the devices may “jump” or spontaneously move together before the surgeon is ready for the devices to couple and may inadvertently trap tissues that are not intended to be joined.
Thus, there still remains a clinical need for reliable devices and minimally-invasive procedures that facilitate compression anastomosis formation between tissues in the human body.